SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4ecdfd00797eda1b46b594069b0259be07f0474859d8204179460776828423d' 
  AND token = 'WyzR7PffTk9Jm+tQq6Ca0RTDGNaMXUmmlUxCwmoowVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}