SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '55e0232412d8a1bbcdcb1b1fd6ec32f870bde360b8658123079a80ec71794a69' 
  AND token = 'DhUU4XZKve+2CMa37LGqBXQEiRK0cU1DV7uekJrv+M8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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