SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83b5c141d1aa9eb73c52e05af854222deb0198b750913be69fdb7db2ba3c6f5a' 
  AND token = 'TRR6T4jc1kOzbtOSS/JUu167QK7Ev1ghBY+TfFGtwyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00072

JSON explain

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