SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1b98ff35f1e28cce0753fd1fede18cf59dcc15b63ad6806c867421da97e429e' 
  AND token = 'L//L1PVy67mhZxdTXYnqT91PiNknn17XG2Wxk1gPN8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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