SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6037eaecf2a719dda61b0fa08dd0192dfce44399179ceaa7ded4d989ea322d9' 
  AND token = '64vCK6EBhjctj32H4jzqRKzjQ6LLlMfMn7XW3tzPhXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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