SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a45b6e012fa149683282dd47627677d0ec6b7cd3e078bb1bd539687b7fc8310' 
  AND token = 'lAvLAK5GRsxufG4uSbfEeExIIoybmOWapEbd1/s8LRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}