SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4193d6c31fb2744f09999bc3aca9d590355babda3ee286623f0fe2c5591c82a' 
  AND token = 'nlagxaZYgczAiqUShRQquPFHvhp5ZmjsVTSECt15eGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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