SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73fa1f2a65a700c8b4c5505a899c7af417c50b2bf3b7177ea77d31fda2d5b5c9' 
  AND token = 'xgCIJwKtv6/LJdIOqwB78LzrreQPNKB1umZmy9X+6ro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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