SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f35032c3744dce196bdb68f5b07f65a4c8f1ab1f941a8580be3f23bc274b8109' 
  AND token = 'IMixmZYSzorgI0x2/ARjTQN1tNefu9l5Y/NAFV/283g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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