SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '512129ff22b843720ddf6fb0c02a897176e440e0390fc9cbe28d16eb52426386' 
  AND token = 'kwDKNt8dmLdQlVBChwGlB9fxOMIEPjgA9K4RFDvoXB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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