SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b1a382eeb36022da59ac7095e41201117dfa5af9f7227fc5ea1f1ed4ea0fd428' 
  AND token = 'mXhX2GhpMPtOmYAlorDnBy5R7/Mg9FYGM4FUnAUEapk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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