SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '434b94140177a539731a88e9ecb0898300a2aa4fc963357128329c43ae1242b2' 
  AND token = 'F/2hNRrTZXSmQYA9h3pOlFzFw7NBNh5vqd6uq3toTF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}