SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac9a22e0b21355ded2d385227dc2556042f6e1717b9b705123b5500369c68dc7' 
  AND token = 'stpf8w7HTNeWAlGsXaxMYu105V5ksupp7QAP+t/LdhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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