SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad1c4e167454dced90074236486c6d6e2446d07e703ee65b7b708c36b71540fd' 
  AND token = '5G4osGRpPZlmBolbppZGKTbXKNVI2Z6/XkqGXHjkvPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}