SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '993ade2ed601cae8b158fc886fda83fb8534c65ac913bcb7490909da85f36d87' 
  AND token = 'VE0Y8cOJfQ3BfNmVbtO4jTHW7fixTKt0adWNVi2ks+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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