SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a07471fe27a502764a1b8337c471b2be4ca93616aeec398f3aebd9e0b584c50' 
  AND token = 'sloVu5p8iAIC2iaS/GtAAsJ/SMw+vAx7kCvYnqQHZK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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