SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e70cd4672b10514607f4c63f75a8b318357f7a1668b30eb934207e1ffcdaf4f4' 
  AND token = 'K0mBHj2993/HoiJZQIT4HyxOvjIkZWTu2iXBeZOUPRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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