SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5c1cf491d466803e96b8f444b3996046f979049b4afda89f8b75c7343479e9af' 
  AND token = 'BTF66pbap9DoRT4FHfmF1+3Wn7H2cCwxz3rTy6UzcEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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