SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86514aff026c47dfe4304f5b235889a436f4653fbaab1443400b8555affa8554' 
  AND token = 'QMxJ4U8WRwtfNae+BbGApuPgYnXQ0M7PfCLPPMxE4J8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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