SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7390231dfe4ab8999bfd391019497425f73562ac362384f2363fb0fd740561d' 
  AND token = 'QmO5RyWLYREG4SZej5VzQwc71juSamASv8kExfJzhtE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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