SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49f316eb2c8447e24e10174d1259701dba62c9490be77c76749a4cdea474a95e' 
  AND token = 'LFJx1RWNrJ4fsiVDMVj/RD4mgyZwG92TBrMveaTnxEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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