SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '857c1aea0afa9efe0e25c3829d4a694611964b36db34375a6b28f4f237b59a4c' 
  AND token = 'GJZFmhLCqnYouPoUh51QH2Cc4SSbVoZyIvDTM5hmYUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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