SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8edb9d8abd189c613f94c972e4f35d16492366fc256993fee556221a66ea266' 
  AND token = '0Tv2xy+CCICjcodQ3XtTEqdKU0VjZGvEQhf+g9bDCWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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