SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dcc3d09252755209da608e9055ad49af2bec5d40aac691a5efbaa00f755aea4' 
  AND token = 'cyyTZz3sLpB1uVtdcRPcmOo4a/z+j9G43HsfhY5dhsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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