SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42c62f10435db9f748f11f0182c190a1d2c1c6832e88e44e3187a5f0bb5b2521' 
  AND token = 'X03u/kCYmYHKYI1EuW5nujzNlak6ZoylkFRTS6KsQQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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