SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce252042d3ee04c008b192bcbf6949e92b30c0fe2ea6c6eb3ac5cea3b7ecda68' 
  AND token = 'LrcyculnwBneN93K4s0KudmutpDvG2qLOhqo0BcUsZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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