SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cad84209f3145096cc739cb221fd826e756394305d756b581e240a9160c354bc' 
  AND token = 'qq1xAZ5D9Xp/nkNSVHwstmrkSupJA+W1hC7hqBnVbHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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