SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3584a98aae42065e287a662740c6b32d8c3134f18b04ef57cab73691adc8828d' 
  AND token = 'N6DENjCNayM13jI3yVsjqnQVVZUD1SMxjHcEV2xSkq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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