SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '421260d0eb9dbd330f425404311394b8ea85fc86c15a3369bd61e505ad9bae10' 
  AND token = '+0YIw1A9Of8FXpE0W6vT9mjY4SXUBIqG32IlSCzfrN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}