SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dcc2e370f16886daf5036ce200e5fef190424fb1632f6e9331fe989f23e115f' 
  AND token = 'u3+gSUnr72jK6Pp5OzbNikQQ5UkOPnbADOkjgQ4PyCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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