SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ef4f6395bd1e7c34f03caeb0e058e14463b42c2dd720e84215b9101b677c833' 
  AND token = '3RFOcCJhaQXFHHyTHuketTczeBQRk9AbqkShAMBTaxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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