SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2971f94081706b9901cd218caa014fd72332506606c96da8da0b139d39085061' 
  AND token = 'H9xhi71yyeTW8XHK1qCkbx3WzntAXT3/aW2C/cH3sRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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