SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c782bb69b96974b1d5b7414073904431ebe66fead486522bfcb962edfe6aa3dc' 
  AND token = 'CT+XSHRvoqx8oTQze1yk2FE1enDSe7/w8+mAHzFhHUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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