SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd520103a87ba5a14c16ae4cacd9b122da1955ccc7b54d240fe497df152c3886' 
  AND token = 'lnEsLmwsrAxFkYRKLadA4UlN2S4ZSXFacQOZBILNzzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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