SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17b99996bd753287b128163f651efe5f4f41a3bda9a045d88494dc9444cedf95' 
  AND token = 'OLU29t4pYzCOwzQh61T3Yr+Va+08nu4UqOQLExap1Vk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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