SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38906cd5c272cfaf93f484afc313cd5f9283e4affa00e06ae5f815e28eb5d1ce' 
  AND token = 'hOXIMY4nfSFv2c+hQ6DNsh8CLQTheM0VJA9fkTK9z2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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