SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5044146ade58453cb08aec21cf4b3054f8a4c1a90b670c5a3d1fb985b8584fc9' 
  AND token = 'vOnQ0CPVE+FAZcB0XhODXBFfRvJB/fKD/Kc1SFMhn5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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