Sandbox

SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b4c5e21773ae186a9628e5f066f0e1b9eb05d5c39b2e3fcab1ea968095987c4a' 
  AND token = 'UP9UEyVPWgRytcV0buQ16zZFt8rzubkAF3IGeRYkCV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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