SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e871cc9cf15326a8f7a22ecc33b0f6415204e1668b2c241d183ae634006cd718' 
  AND token = 't9EaPgbUdScCZ8gFhhewBxuzmaUBNlvFo8SCHuZRMS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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