SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6114497df20a740a73f480110d1383b24c010853e6661d44932a8b4a15df237' 
  AND token = 'Z2la11xPPblMFo6oSb5V1ENIvLVr6KyYfczZ2ubegiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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