SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08321b912ab4f27085e995b6b05a530534ca648ffc5236887c4f3f4f3ddeb189' 
  AND token = 'itahr42HjXLAUMEV93JudcYgKdhsu3TWmqzYnhPHR5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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