SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c4309a16ea6103b8ab8f576276e2cffa2a7978736ab94cce32f4a6536600ff1e' 
  AND token = 'RJvMKKDWKpMiPCZ/ZyF9W4k0euM/hTq4BatksZ+gxUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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