SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4ded35340e228e1ca2397f098c7298ccfe08dadef898480dcc35a2aba1dc35c' 
  AND token = 'YJAWUfgQqRh662R7ePpaxV3JC8gXmPvnTYPMgASOPTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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