SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2fbe2c32847aaec105655ae817682b2a8423a78222aa989b2a82752a1693266' 
  AND token = 'CIw/h8VnyWz6vR6GSlKqGAUhcJAThbmhgZhrumXgFH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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