SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f857536439dad0afc1663db8929079b691ec506d0683e63f2563f380b620083e' 
  AND token = '2OGhpyDbsa/e12ciTXNOkf8gzfb2qdQe2H+Xpc1Yq44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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