SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e776214d48248ac9844fc7c43e48a434bd9655b4c367f3f50d10037760c6971a' 
  AND token = 'cWmo6YDDwAM36ZCtkjWQ5VANkpu16Q45I2zJizNHj7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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