SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63005762b2c557f4b28f33957e2ae91fa0a21960990cbc46ec8d877632bafb34' 
  AND token = 'yO6fF7k/A+3Vrw2kbdziswvMqk34VzTZ6OYmGSiPBpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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