SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6f11303872c806567e9b56753212b3f00d631dec0b192edacc7069ec16252b76' 
  AND token = 'pTa/Zbrg0NvSHqhZpQvxZxQbuUnjkQ0y/sWLXG30idY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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