SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8faf07693f60063783a69d269c0514b4e0b8770fab18bf211b2d56df6c2ea9b3' 
  AND token = 'BSwEvV6rQdu4j0n/euGWSQDlaH+y50UmaVpUKRsng38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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