SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8e80e35413fb515d637a587f4696192f757109b5ea25a34a2efbb6c0dcd4f07' 
  AND token = 'jMVhB7ij1xM6NUoG+m7wzvOLFhvaIkcWQYGuV3ws/lU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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