SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5fb59f6e6f3ef5d512dfde1d8ecb7556ca1bdfbd38aa923e2ecdcd9ad200436' 
  AND token = 'n/ysVkM0A/oYTnuAgto31Jpzeo1iI46oVoEPxqqN9QU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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