SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '091f621c1f1bb1118202fe723a294b5ac917959ee7f97cc67f469f7429fa1801' 
  AND token = 'zlIBRjcBPDMxtzeuXE6jVUoOvH8NUUBhpB1q8Fgtfb8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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