SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd247ce1fa28d146c676824383b72f33d2b82f9bb9eae98fb1dd0905443b3c1a1' 
  AND token = 'MqLN+Yf83gSaF662EygriWRvmhLpe/0wjx5B2CTAGJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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