SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd0c44fafc49507ef46e99f7f0713ff3bb0936769a5f67d3073d7c390613b9a57' 
  AND token = '4CQWfOFRYFAJjQuBr8MjAvbfeJNIHwYzZXsC87ReAG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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