SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8a2ed19b497d34867f3980aaf627bd4581fa7252591ed97352c56bec3b6dbef' 
  AND token = 'K2rIomYVaWEl51W7c2aFlCZX2SXzaQDUDN+Ufo8ABQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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