SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79a3892f4cfc5419a2562b5e3b9c9c01bd29f44f35f94b5b85d0c371ae83ef2a' 
  AND token = 'fHLitfgeDC10pv6IRYoM7FEwjV/BTEY7GhdQe6F8s9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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